Polypropylene Polymer Matrix Research Articles

Mechanical Performance of Luffa Fiber Reinforced Polypropylene Composites using Injection Moulding

This study aims to investigate the mechanical properties of polypropylene polymer matrix composites reinforced with luffa fibers. It also tries to reduce polypropylene content in the manufacturing process by incorporating natural fibers such as luffa. Natural fibers offer good mechanical qualities and are inexpensive. They have a high specific strength, are environmentally benign and are biodegradable. The fiber is first alkaline-treated and then heated on the surface in the sun. The fiber is then powdered using a ball milling technique and mixed with polypropylene in various weight proportions. The composite samples were prepared using the injection molding process. The prepared samples were tested for mechanical characteristics such as tensile strength, flexural strength, impact strength and hardness. The percentage increase are 8.32, 2.56, 23.07 and 7.73 respectively as compared with the control sample. The research demonstrates that adding the right amount of natural fiber with the polymer can significantly improve their mechanical properties. From the study, it is concluded that natural luffa fiber can be used to minimize the content of polymers in structural applications.

Visualization of Macrophase Separation and Transformation in Immiscible Polymer Blends

Visualization of Macrophase Separation and Transformation in Immiscible Polymer Blends

Structural and Mechanical Properties of Lignite Fly Ash and Flax-added Polypropylene Polymer Matrix Composite

ABSTRACT Flax fiber-containing polypropylene-based polymer matrix composites (PMCs) with different lignite fly ash (LFA) contents were synthesized using the formula (80 − x) PP − 20 F – x LFA (where x = 0, 2.5, 5.0, 7.5, and 10.0 wt.%) and analyzed. The added LFA acted as a filler material in the polymer network to re-formulate the microstructure of PMCs. The structural changes in the PMCs were induced to alter their thermal stability and mechanical strength. A linear increase in T g, density, and compressive strength values was observed up to addition of 10 wt.% LFA in the prepared PMCs. Fourier transform infrared spectra revealed the structural changes that occurred in the polymer network for all the samples during the addition of LFA. Results of the X-ray diffraction studies confirmed the crystalline phase of the added LFA in the PMCs. Contact angle and surface energy studies showed a higher contact angle and lower surface energy in the PMC sample containing 5 wt.% LFA. The low wear depth in the sample containing 5 wt.% LFA confirmed its better wear than other samples. The obtained results confirmed that the flax fiber-added polypropylene composite with 5 wt.% LFA is suitable for aerospace, construction, and automobile applications.

An empirical research on areca fiber polymer composite for automotive components in modern industry

Recently the development of natural fiber composites instead of synthetic fiber has led to eco-friendly product manufacturing to meet various applications in the field of automotive, aerospace, construction and manufacturing. The use of natural fibers offers an alternative to the synthetic reinforcing fibers because of their good mechanical properties, low density, renewability, and biodegradability. Different natural fibers are generally utilized as reinforcement in thermoplastic polypropylene (PP) matrix to prepare composites. In this paper, experimental investigation of natural fiber i.e., Areca fiber reinforced with polypropylene polymer matrix is done to analyze the Mechanical and Thermal properties of polymer composite. The modification of composite is done by using Maleic Anhydride (MA) during preparation of composite material. Different fractions of composites with 5 wt%, 10 wt% and 15 wt% fiber content were prepared in twin extruder and 3 wt% of Maleic anhydride was added during the mixing process. Mechanical and Thermal properties such as Tensile strength, Bending strength, Elongation at break, Water absorption capacity, Heat Distortion Temperature (HDT) of areca fiber and PP composites were investigated. The above composite polymers are used in manufacturing the components of automobiles such as passenger car interiors, indicator cover, door panels, door pockets, rear view mirror covers.

Fabrication of Polypropylene (PP)/Poly Trimethylene Terephthalate (PTT)/Nanoclay Nanocomposite Fibers with Tailored Properties

The main aim of this study was to deal with one of the major drawbacks of polypropylene (PP) fibers, i.e., low resiliency and low dyeability, by incorporating polytrimethylene terephthalate (PTT) fibrils, as a dispersed material, and organoclay, as a nano-filler, into the PP polymer matrix. The presence of 10 wt% of PTT and 0.5–1 wt% organoclay in the PP nanocomposite fibers led to an approximately 18.5% and 45.5% increase in the resilience behavior and dye uptake, respectively, compared to pure PP fibers, without using highly toxic carriers. The lowest mean diameter of the nano-fibrils was 75 nm for the hot drawn nanocomposite fiber samples as measured by scanning electron microscopy (SEM). The results of DSC indicated that the presence of both PTT and organoclay significantly influenced the crystallinity of the PP which also confirmed their nucleating effects in the nanocomposite fiber.

Graphene oxide synthesis for composite material preparation

Graphene, a material formed by carbon atoms with sp2 hybridization in a hexagonal arrangement, has differentiated characteristics in comparison to commercial materials such as high flexibility, high electrical and thermal conductivity, and strong resistance due to the organized structure of the material and can be applied in several branches of research. The best-known method for the production of graphene is the exfoliation of graphite using the methodology proposed by Hummers, in which the commercial graphite is oxidized obtaining as final product the graphene oxide that can be converted into graphene. In this study, the Hummers methodology was used in the oxidation of synthetic graphite and graphene nanoplates of 5 μm and 15 μm. The obtained materials were characterized by FTIR, RAMAN and XRD, allowing to observe the best synthesis to be used in the production of graphene oxide. Then, composites were prepared using the graphene oxides obtained as filler. In order to obtain them, different mass quantities of graphene oxides (1%, 3% and 5% in relation to the polypropylene polymer matrix) were used, demonstrating by the strain tensile stress tests that the composite materials have results more satisfactory than pure polypropylene.

Fabrication of Polypropylene/Poly (TrimethyleneTerephthalate) Blend Fibers with Highly Improved Resiliency and Preserved Mechanical Properties

The main aim of this study was to deal with one of the major drawbacks of polypropylene (PP) fibers, i.e. low resiliency, by incorporating poly (trimethylene terephthalate) (PTT) nano-fibrils as a dispersed material into the PP polymer matrix. Thanks to the special helical shape of the PTT polymer backbone, the incorporated nano-fibrils of the PTT polymer strengthened the resiliency of the blend fibers. The presence of 10 and 15 wt% of PTT in the blend fibers led to an approximately 20% increase in the resilience behavior, compared to pure PP fibers, with the mechanical properties of the PP matrix preserved. The development of the fibrillar structures during the different steps of the melt spinning process was confirmed by scanning electron microscopy (SEM), and the lowest mean diameter of the nano-fibrils was 64 nm for the hot drawn blend fiber samples consisting of 10 wt% of PTT. In summary, we suggest the optimized blend fiber samples produced in this research will be a promising candidate for a wide range of engineering applications.

Study of the Effect of Compatibility Agents in the Incorporation of Rice Hull Ash in Polypropylene Compounds: Mechanical Properties

The present work aimed at incorporating the rice hull ash (RHA) into a polypropylene polymer matrix. The methodology applied was the case study, whereby the rice hull, residue generated during the grain extraction, was used in the present study. The samples were prepared with the addition of a coupling agent (silane) with 10% by mass in relation to the filler, to improve the characteristics of the ash/ matrix interface. The tensile test results showed that the modulus of elasticity increased proportionally to the addition of the RHA contents, promoting an increase in the material stiffness. The micrographs showed excellent adhesion between the RHA particles and the polymer matrix. proving the coupling, because there was a good wettability array load due to the use of the coupling agent. The results show the feasibility of use of CCA in the composite with PP.

Modulating and tuning relative permittivity of dielectric composites at metamaterial unit cell level for microwave applications

Dielectric materials with desirable relative permittivity (εr) may not be readily available in nature and are usually difficult to be tailored precisely. We hereby predict and experimentally achieve the flexible tuning of εr for dielectric materials at the unit cell level in microwave range, as inspired by the recent developments in metamaterials. A series of composite dielectric stock sheets with εr in the range of 3–7 and low loss tangent (tanδ<0.01) were successfully fabricated by dispersing different volume fractions of TiO2 nanoparticles into polypropylene polymer matrix. To further enable the flexible tuning of εr, sub-wavelength holes with different diameters were drilled on the composite dielectric sheets based on 5×5×5mm3 metamaterial unit cells. The resultant effective εr of the metamaterials conformed well to the simulation results by CST STUDIO SUITE® software. By utilizing the drilled-hole PP/TiO2 composite metamaterials, a potential scheme to implement a dielectric gradient index lens with discretized shells of varying εr is presented. This drilling-hole approach to modulate and tune the effective εr at the metamaterial unit cell level can be generalized to produce a variety of desirable permittivity values with great flexibility. The applications of these materials can be easily extended to other microwave or optical devices including cloaks, lenses, and beam shifters.

Nanoscale, zero valent iron particles for application as oxygen scavenger in food packaging

Abstract Oxygen scavengers which are based on oxidation of iron powder dispersed in a polymer matrix are established in the packaging industry. They protect foods from oxygen. The iron particles have a diameter of several micrometers, which is too high to allow thin layers in multilayer film structures. A promising alternative is a developed nanoscale oxygen scavenger which is subject of this study. The aim of this study was to evaluate the oxygen absorption rate and the oxygen absorption capacity of nanoscale iron at 100% relative humidity and at dry conditions. Nanoscale oxygen scavengers (zero valent iron particles) were synthesized. Their reactivity was tested. Furthermore, they were blended with a silicone matrix. The nanoscale oxygen scavenger absorbed oxygen in wet (100% relative humidity) and dry conditions. At 100% relative humidity the reaction rate of the powder was two to three times higher compared to non-nanoscale iron powder. The absorption rate of the nanoscale iron dispersed in a silicon carrier was at least ten times higher at 100% relative humidity compared to a commercially available iron based oxygen scavenger in a polyethylene or polypropylene polymer matrix.

Microwave dielectric properties of composites consisting of MgAl2O4 filler synthesized by molten-salt method and isotactic polypropylene polymer matrix

MgAl2O4 particles were synthesized through the solid-state reaction method (MAO-S) or molten-salt method (MAO-M). The crystallinity, particle size, and crystal structure of spinel-structured MAO-S and MAO-M particles were characterized and these particles used as dielectric fillers were filled into an isotactic polypropylene matrix, up to 30 vol % filler concentration. Significant differences in the degree of inversion (λ), which represents the cation distribution in tetrahedral and octahedral sites, were obtained for MAO-S and MAO-M by solid-state NMR measurements and the λ value of MAO-S fired for 10 h was 0.39, while that of MAO-M fired for 10 h was 0.64. The dielectric constant of MAO-S- or MAO-M-filled composites increased from 2.4 to 3.7 with increasing filler concentration and was consistent with the Bruggeman model. The dielectric loss and thermal conductivity of the composites were remarkably improved by the addition of the MAO-M filler, depending on the increase in the duration of firing, and were 1.74 × 10−4 and 0.62 W/(m·K), respectively. The coefficient of thermal expansion and the temperature coefficient of the dielectric constant of composites also depended on the filler concentration.

Feasibility of the recovery of uranium from alkaline waste by amidoximated grafted polypropylene polymer matrix

The amidoximated grafted polypropylene polymer matrix was prepared by post irradiation grafting of acrylonitrile (AN) onto thermally bonded non-woven matrix of poly(propylene) sheet using electron beams. This precursor polymer was reacted with hydroxylamine to convert AN to poly(acrylamidoxime) (AO) groups, and conditioned by treating them with 2.5 % KOH at 80 °C for 1 h. The polymer matrix was having the degree of AN grafting ~106 wt% and its subsequent conversion to AO groups ~70 %. The water uptake capacity of AO polymer matrix were found to be 100 ± 5 % (w/w). Quantitative recovery of uranium from alkaline waste (ammonium diuranate supernatant) solution was achieved by this polymer matrix. The other radionuclides present in the waste solution were not extracted by the polymer matrix. For all other radionuclides, the uptake was found to be <6 %.

Effects of Synthetic and Processing Methods on Dispersion Characteristics of Nanoclay in Polypropylene Polymer Matrix Composites

This work presents the effect of synthetic procedures (extrusion and casting) on the dispersion characteristics of nano layered silicate clay particles in the polypropylene (PP) polymer matrix. Three different molecular weights PP samples are taken and filled with nanoclay of 1 wt% and 3 wt%, and these nanocomposites were synthesized by using an extrusion or casting methods. The X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM) is used to characterize the structure and morphology of nanocomposites. Rheological and mechanical results show that the extruded products are better than that of cast products. The outcome of this work is discussed in this paper.

Structure and properties of polypropylene/organic rectorite nanocomposites

AbstractMelt blending using a twin-screw extruder was used to prepare composites of polypropylene (PP)/organic rectorite (PR). The organic rectorite (OREC) was modified with dodecyl benzyl dimethyl ammonium bromide (1227). Wide-angle X-ray diffraction (WAXD) and transmission electron microscopy were used to investigate the dispersion of OREC in the composites. The d spacings of OREC in PR composites was greater than in OREC itself. The dispersion of OREC particles in the PP polymer matrix was fine and uniform when the clay content was small (2 wt.%). The rheology was characterized using a capillary rheometer. The processing behaviour of the PR system improved as the amount of OREC added increased. Non-isothermal crystallization kinetics were analysed using differential scanning calorimetry. It was shown that the addition of OREC had a heterogeneous nucleation effect on PP, and can accelerate the crystallization. However, only when fine dispersion was achieved, and at lower rates of temperature decrease, was the crystallinity greater. Wide-angle X-ray diffraction and polarized light microscopy were used to observe the crystalline form and crystallite size. The PP in the PR composites exhibited an a-monoclinic crystal form, as in pure PP, and in both cases a spherulite structure was observed. However, the smaller spherulite size in the PR systems indicated that addition of OREC can reduce the crystal size significantly, which might improve the ‘toughness’ of the PP. The mechanical properties (tensile and impact strength) improved when the amount of OREC added was appropriate. Dynamic mechanical analysis showed that the storage modulus (E′) and loss modulus (E″) of the nanocomposites were somewhat greater than those of pure PP when an appropriate amount of OREC was added. Finally, thermogravimetric analysis showed that the PR systems exhibited a greater thermal stability than was seen with pure PP.

Conducting polymer blends prepared from polyaniline with n‐dodecylbenzenesulfonic acid zinc salt as the secondary dopant

AbstractA red‐shift of the UV–vis spectra of n‐dodecylbenzenesulfonic acid doped polyaniline (PANI (DBSA)0.5), resulting from the secondary doping of polyaniline backbones, was found in the presence of n‐dodecylbenzenesulfonic acid zinc salt (Zn(DBS)2). It is proved to behave as steric hindrance spacers to induce the extension of the conjugation length through the straightening effect on the polyaniline backbones and the obtained mixtures (PANI(DBSA)0.5 plus Zn(DBS)2) can be used as master batch materials (MB‐13) for blending with regular polypropylene polymer (PP). The thermal degradation accompanied with loss of conductivity for MB‐13 can be delayed to over 250°C when enough Zn(DBS)2 was secondarily doped on PANI(DBSA)0.5., which allow the performance of its blending with other nonconducting/regular polymers possible. Below 80 rpm, increasing shear rates would induce higher viscosity difference between the MB‐13 and PP matrix, resulting in elongation of MB‐13 in the PP matrix and higher conductivities of the polyblends. The deviation from the Taylor equation, which is used to estimate the degree of elongation for a polyblend, started when shear rate is over 80 rpm. The leakage of Zn(DBS)2 out of MB‐13 can be confirmed by comparing the DSC thermograms and X‐ray diffraction patterns with that of neat PP. Gradual deformation for the conductive fillers (MB‐13) and a well‐defined and expanded layered structure can be found when processing time is below 15 min with 60 rpm shear rate. The layers started to shrink back after 15 min of procession with the loss of the Zn(DBS)2 from MB‐13 in the PP matrix. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Cd(II) transport across supported liquid membranes (SLM) and polymeric plasticized membranes (PPM) mediated by Lasalocid A

Cd 2+ ion transport is observed through two different membrane systems (supported liquid membrane (SLM) and polymeric plasticized membranes (PPM)) containing Lasalocid A as carrier and 2-nitrophenyl octyl ether (NPOE). In PPM, the cellulose triacetate (CTA) is the membrane core and the NPOE a plasticizer, while in SLM the latter compound acts as a carrier solvent in the porous polypropylene polymer matrix. A comparison between the transport fluxes at same Lasalocid A concentration in the membrane for both membrane systems is proposed. The divergence between the two systems depends on the carrier concentration. At high carrier content, the PPM system becomes more efficient than the SLM system. A long-term stability and good durability of the PPM membrane was observed.

A generic organometallic approach toward ultra-strong carbon nanotube polymer composites.

Multiwalled carbon nanotubes have been functionalized using n-butyllithium and then covalently bonded to a chlorinated polypropylene. The following addition of the polymer-grafted nanotubes to the chlorinated polypropylene polymer matrix resulted in significant increase of mechanical properties. As nanotube content is increased to 0.6 vol %, Young's Modulus increased by a factor of 3, while both the tensile strength and the toughness increased by factors of 3.8 and 4, respectively. This covalent functionalization enables us to get an efficient dispersion and excellent interfacial stress transfer, potentially leading to new ultra-strong polymer composite materials.

Ciba Specialty Chemicals buys inorganic oxygen absorbers from BP Amoco

Oxygen scavengers which are based on oxidation of iron powder dispersed in a polymer matrix are established in the packaging industry. They protect foods from oxygen. The iron particles have a diameter of several micrometers, which is too high to allow thin layers in multilayer film structures. A promising alternative is a developed nanoscale oxygen scavenger which is subject of this study. The aim of this study was to evaluate the oxygen absorption rate and the oxygen absorption capacity of nanoscale iron at 100% relative humidity and at dry conditions.Nanoscale oxygen scavengers (zero valent iron particles) were synthesized. Their reactivity was tested. Furthermore, they were blended with a silicone matrix. The nanoscale oxygen scavenger absorbed oxygen in wet (100% relative humidity) and dry conditions. At 100% relative humidity the reaction rate of the powder was two to three times higher compared to non-nanoscale iron powder. The absorption rate of the nanoscale iron dispersed in a silicon carrier was at least ten times higher at 100% relative humidity compared to a commercially available iron based oxygen scavenger in a polyethylene or polypropylene polymer matrix.